Originally Posted by
BenFenner 
I read the pro-billet argument in the article Miko linked in the other thread. I'm convinced those arguing for billet don't understand how the forging process works and what it actually does to the grain of the metal. Nor do they understand how machining a forged billet slug ruins the strength gained from the initial forging.
Did you realy read the complete article and then make that statement. There seems to be some qualified people giving their opinion. I mean damn the guy from scat makes cranks and rods.
Tom Lieb Of
Scat:
"A forging is not as strong as billet because the forging process stretches and shears the grain structure. A forging starts out as round bar of metal and gets twisted and turned to make the rod throws. What used to be centerline of the bar is now offset, and the grains get stretched, traumatized, and weakened, although some sections of it are substantially stronger than in a casting. With billet, there are no stress riser areas because the grain structure runs parallel to the length of the entire crank. Forgings are stronger than billet in bolts and axles because the metal isn't being stretched and sheared. There isn't a single Top Fuel, Funny Car, Nextel Cup, or F1 team that uses forged cranks, so you have to ask yourself why."
Judson Massingill Of The SAM:
"Up to 600 to 700 hp, forgings are every bit as good as billet cranks, given adequate journal overlap. However, when you start reducing the overlap with long strokes and small rod journals to reduce bearing speed, billet comes out on top. In our motors, billet lets us get away with less journal overlap."
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